Numerical modelling techniques applicable for the prediction of residual stresses and distortion due to mild steel DH36 frictions stir welding

摘要

Friction stir welding involves a multi-physics phenomena, including visco-plasticity, material flow, metallurgical transformation, heat generation, thermal straining and structural interaction. Numerical modelling provides an efficient and cost effective tool capable to analysis and predict the different phenomena. This study integrates different numerical modelling strategies to ultimately develop a robust yet computationally efficient modelling technique capable of predicting residual stresses and distortion due to FSW. A computational efficient local-global numerical model capable of predicting the material visco-plastic flow, thermal transients, stir/heat affected zone, residual stresses and distortion developed due to friction stir welding of DH36 plates is described. Different thermo-elasto-plastic modelling strategies ranging from analytical to transient numerical models are explored and the most robust and computational efficient strategy is identified through cross-reference with the realistic experimental test results.